Most foods are processed in some way before reaching the consumer. For example, vegetables may be washed, trimmed, blanched, and than frozen prior to distribution. Meat products also require significant processing before reaching the consumer. At the very least, the animal carcass is cut into segments and the larger cuts of meat or fillets are cut from these initial segments. Other usable elements remaining after separating the larger cuts of meat are then separated from the remaining unusable elements such as bone and then ground or chopped, mixed, and then commonly frozen for distribution.
Foodstuffs are inevitably exposed to microbes as the foodstuffs are processed or handled. Microbes are part of the natural decay process of organic material and may be deposited on foodstuffs through the air or by contact between the foodstuff and contaminated equipment or other material. Although some microbes may be relatively benign, others contribute to spoilage and some can cause serious illness. Lactic acid producing bacteria are examples of benign microbes, while some strains of E Coli, Salmonella, Listeria, and Staph bacteria are examples of pathogenic microbes which can cause serious illness when ingested by humans.
Even with careful processing practices, foodstuffs may be exposed to pathogenic microbes during processing or initial handling. The risk of illness from dangerous microbes which may be present in foodstuffs is reduced by a careful handling and cooking by the consumer. For larger cuts of meat for example, dangerous microbes may commonly only be present on the surface of the meat and are readily killed in the cooking process.
Ground or chopped and mixed foodstuffs, including ground beef, may carry dangerous microbes which are killed only after thoroughly cooking the material. The reason for this is that dangerous microbes residing at the surface of a larger piece of the foodstuff may be distributed throughout the final ground or chopped product as the large piece is ground and mixed together with other pieces. Thorough cooking is required in order to kill microbes residing in the center of a piece of ground and mixed foodstuff.
It is therefore desirable to control the growth of microbes and reduce microbe content in foodstuffs. Microbe content and growth in foodstuffs may be reduced by applying chemical additives or preservatives to the foodstuff. These chemical additives or preservatives, however, may not be acceptable to consumers, or may have undesirable effects on foodstuffs.
Alternatively to chemical additives or preservatives, heat may be used to kill microbes in foodstuffs. However, heat processing or sterilization often has undesirable effects on the quality or characteristics of the foodstuff and may make the food product undesirable to the consumer.